JPH02263155A - Bearing mechanism crack detection device and method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a crack detection device and method for a bearing mechanism.
In particular, the present invention relates to an apparatus and method for detecting microcracks that occur in a 111+1 bearing mechanism having rolling bearings while the mechanism is in operation. (Prior art and its problems) Conventionally, in a rolling bearing mechanism, microcracks occur inside the bearing ring, reach the bearing ring surface, and occur when a rolling element passes through an open crack -1-. There is a known device that detects the occurrence of a crack by detecting the vibration of the bearing mechanism and comparing the detected value with the normal vibration value of the bearing mechanism when no crack occurs. However, with this conventional device, the occurrence of cracks can only be detected when a part of the surface of the bearing ring peels off (falls off) and an 11-1 part is formed on the surface, and micro-cracks that have not yet reached the surface can be detected. could not be detected. On the other hand, acoustic emissions (Ac
ousl, ic emission (hereinafter referred to as rAEJ) during the operation of the rotating equipment in which the mechanical seal is installed, and the signal level or frequency characteristics of the detection signal are determined to prevent cracks from occurring. A device for detecting the occurrence of microcracks inside a mechanical seal by comparing it with normal conditions is already known, for example, from Japanese Utility Model Application Publication No. 172056/1983. However, although this latter conventional device can in principle detect the occurrence of microcracks that have not reached the surface of the mechanical seal, when the rotating equipment is in operation, the signal detected by the AE sensor does not include microcracks. Based on the occurrence of non-AE-based shoe sounds, and since the micro-cracks are small compared to the AE multiplied signal shoe sounds, they cannot be detected in the early stages of micro-cracks, but after the cracks have grown considerably. The problem was that it was detected for the first time. (Object of the Invention) The present invention has been made to solve the above-mentioned problems, and it is possible to reduce the micro-cracks that occur in a bearing mechanism having a rolling bearing by reducing the acoustic emissions generated from the micro-cracks while the bearing mechanism is in operation. (AE) can be detected early and accurately by detecting it multiple times.
The purpose of LI is to provide a crack detection device and method for a bearing mechanism. (Means for Solving the Problems) In order to achieve the second object, the present invention provides a stationary body, a working body, and a space between the stationary body and the working body at equal intervals in the direction of operation of the working body. A bearing mechanism comprising a plurality of rolling elements disposed in the bearing mechanism and movable in the operating direction, a crack detection means for generating a characteristic signal in response to a crack generated in the bearing mechanism, and a rolling element for detecting the operating state of the rolling elements. a moving body state detection means; an operating body state detection means for detecting the operating state of the operating body; 1)
j) A rack detection means, a rolling element state detection means 9, and a control means connected to the operating body state detection means. (Function) Immediately after the characteristic signal is input from the crack detection means,
Based on the operating state signal input from the rolling element state detecting means or the operating member state detecting means, determine the condition of the operating state signal to which a characteristic signal should be input from the crack detecting means from next time onwards. 1, and then monitors the operating state signal, and if a characteristic signal is input from the crack detection means when an operating state signal that satisfies the condition is input,
A value indicating the input of the characteristic signal or a value indicating the intensity of the characteristic signal is added to the previous value and accumulated, and it is determined that a crack has occurred in the bearing mechanism based on the accumulated value. Furthermore, when the cumulative value exceeds at least one predetermined value or when the rate of increase in the cumulative value exceeds a predetermined value, it is determined that a crack has occurred in the bearing mechanism. Immediately after the characteristic signal is manually input from the crack detection means, a characteristic signal is inputted from the crack detection means from the next time onwards based on an operating state signal input from the rolling element state detection means or the operating body state detection means. Should 1);
Determine the conditions for the operating state signal j, then monitor the operating state No. 11, and if a characteristic signal is input from the crack detection means when an operating state signal satisfying the conditions is input, the characteristic detecting the amplitude value or duration of the signal, and determining that a crack has occurred in the bearing mechanism based on at least one of the rate of change in the distribution of the amplitude value or duration detected during a certain minute time; do. (Example) Examples of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a bearing mechanism that is a radial bearing, and the reference numeral 1 in the figure indicates an inner ring, and the inner ring 1 is fitted onto a rotating shaft 102 and integrally moves in the direction of arrow a, for example. Rotate 3000 revolutions/rotation. The rotating shaft 102 and the inner ring 1 are supported by a stationary outer ring 3 via a plurality of roller-shaped or ball-shaped rolling elements 2 arranged around the rotating shaft 102 . A cart frame 4 is fixed to the outer ring 3,
A load in the direction indicated by the arrow is applied to the outer ring 3 via the load frame 4. The plurality of rolling elements 2 are arranged at equal intervals in the circumferential Jj direction of the inner ring 1 by a retainer (not shown), and rotate in the direction of arrow a at a rotation speed slower than the rotation speed of the inner ring 1 as the inner ring 1 rotates. . The bearing mechanism shown in FIG. 1 includes a rolling element position sensor 5, which is a part of the crack detection device of the present invention. Inner ring position sensor6. ΔE
A sensor 7 and a protrusion 101 are provided. The rolling element position sensor 5 is a sensor consisting of a photosensor fixed to the outer ring 3 so as to face the trajectory of the rolling elements 2, and emits a pulse every time one of the rolling elements 2 passes the trajectory opposite to the sensor. Output. The rolling element position sensor 5 is not limited to a photo sensor, but may also be a strain gauge, an eddy current detector, or a vibration meter. It may also be configured with an AE sensor or the like. The protrusion +01 is provided on the outer peripheral surface of the rotating shaft 102 at a position in contact with the inner ring j. The inner ring position sensor 6 is connected to the protrusion 1
The sensor 6 is a photo sensor fixed to the outer ring 3 so as to face the passing trajectory of the projection 1.
01 outputs a pulse every time the sensor passes through an opposing trajectory. A proximity switch may be used as the inner ring position sensor 6. The AE sensor 7 is fixed to the outer ring 3 and transmits A to the outer ring 3.
Detect IE. In this AIE, strain energy accumulated inside the contact surface with the rolling elements 2 of the inner ring 1 or the outer ring 3 is applied to the contact surface by the rolling elements 2 passing through the contact surface (i.e., plastic +1 to ij). Microcracks are generated inside the contact surface when they are opened due to change or material change (for example, conversion from austenite to martensite) or fracture.
Or, it grows, and the opening shock propagates as an elastic wave. The elastic waves are generated by the micro-cracks on the inner ring 14.
When it occurs, it reaches the Δ1Σ sensor 7 via the rolling element 2, and when it occurs on the outer ring 3, it reaches the Δ1Σ sensor 7 directly. Furthermore, as the crack grows or as the pressure applied to the crack increases, the intensity of the elastic wave increases. FIG. 2 is an electrical circuit diagram of a crack detection device for a bearing mechanism according to the present invention. In the figure, the AE sensor 7 includes an amplifier 21, a bandpass filter 22 for the 100 to 500 ktlz band. It is connected to the square wave generator 24 via the main amplifier 23, and the output '1'1 of the square wave generator 24 is connected to the square wave generator 24 through the main amplifier 23.
is supplied to the input/output circuit 35 of the microcomputer. That is, as shown in FIG. 4, the output of the Δ13 sensor 7 (
Fl), preamplifier 21. After being amplified by the main amplifier 23 and removing low and high frequency components by the band pass filter 22 (b), the rectangular wave generator 24 performs envelope detection (C), and the detected signal (solid line in C) reaches a predetermined threshold. Value (dashed line in brackets)
A rectangular wave '['1 (e) is output only when the value exceeds . The rolling element position sensor 5 is connected to an amplifier 25. It is connected to a discriminator 27 via a waveform shaper 26. That is, the output of the rolling element position sensor 5 is amplified by the amplifier 25, shaped by the waveform shaper 26, and outputted as a pulse by the discriminator 27. Since the output pulse of the Jr separate device 27 is generated every time each of the rolling elements 2 passes the opposing track monitoring point of the rolling element position sensor 5, the frequency fo(IIZ) of the output pulse is equal to the frequency fo(IIZ) of the rolling element 2. corresponds to the number of times the sensor passes through the monitoring point of the sensor 5 in one second. Connect the output of the separate device 27 to the pulse converter 28 and the reset terminal I of the counter 29.

The output side of the pulse converter 28 is connected to the input terminal I of the counter 29. The output side of the counter 29 is connected to the input/output circuit 35 of the microcomputer. The pulse converter 28 converts the output pulse of the frequency fo from the block I divider 27 into a pulse having a frequency (1)×fo) which is multiplied by a PC integer. This changes the monitoring point of the rolling element position sensor 5 to 1 of the rolling element 2.
This corresponds to dividing the period from when one of the rolling elements 2 passes until the next one of the rolling elements 2 passes by 1]. The counter 29 is
The pulse of frequency Pfo input from the pulse converter 28 through the input terminal -1 is inputted by the pulse L-L, and the count value 'I
2 is supplied to the input/output circuit 35. The callan i・value T2
is reset to zero from the discriminator 27 by the human input signal (pulse of frequency fo) through the reset end/[≧. It counts from zero to (P-1) while passing the monitoring point of the sensor 5.Also, if the total number of rolling elements 2 arranged at equal intervals is Q, the counter 2
The count value 1 in 9 is the rotation angle of the rolling element 2 (360/P
Q) It corresponds to degrees. The value of [2] above is determined in relation to the width of the waveform (solid line) after envelope detection of the E-sensor output shown in FIG. 4(C). That is, when the width is narrow, the value of [) is set to a large value. Similarly to the rolling element position sensor 5, the inner ring position sensor 6 also has an amplifier 30. The discriminator 32 is connected to a discriminator IJ 32 via a waveform shaper 31, and the discriminator 32 has a protrusion 1 that rotates as the inner ring 1 rotates.
01 outputs a pulse every time the inner ring position sensor 6 passes a monitoring point on the opposing track. The frequency f+(Ilz) of the external output pulse is 1 when the protrusion 101 is
This corresponds to the number of times the sensor 6 passes the monitoring point per second. The output side of the discriminator 32 is pulse conversion! 1l) 33 and also to the reset terminal 1 of the counter 3/l, and the output side of the pulse converter 33 is connected to the input terminal 1 of the counter 34. The output side of the counter 34 is connected to an input/output circuit 35 of the microcomputer. In the pulse converter 33, the frequency f1 output from the discriminator 32
l) Convert the pulse into a pulse having Q times the frequency (PQXf+). This corresponds to dividing the cycle period from when the protrusion 101 passes the monitoring point of the inner ring position sensor 6 to when it passes the next time to I)Q. The counter 34 counts pulses of frequency PQf+ input from the pulse converter 33 via the input terminal 1, and supplies the count value '1'1 to the input/output circuit 35. That Karan I・fi! : f is reset to zero at the input 4Ij of the input signal (pulse of frequency f1) which is input manually from the discriminator 32 via the reset terminal R. In other words, the counter 34 changes from zero to (1)Q-] between when the protrusion 101 passes the monitoring point of the inner ring position sensor 6 and when it passes the next time.
Count up to. In other words, the count value l of the counter 34
corresponds to the rotation angle (360/l)Q) degrees of the protrusion 101. 01, the count value l of the counter 29 also corresponds to the rotation angle (360/P Q ) degrees, so the count value 1 of the counter 29 and the counter 34 is
and corresponds to the same rotation angle of the protrusion 101 (i.e., the inner ring 1). Therefore, the count values of both counters 29 and 34 can be considered in correspondence to the rotation angles of the rolling elements 2 and the projections 101 (inner ring 1). In other words, it corresponds to a count value of 1 (36
0/PQ) degree is one unit, and a multiple of the unit angle (corresponding to the Curran I value) is the rotation angle. For example, rolling element 2
The angle formed by two adjacent ones is represented by I], and the angle at which one of the protrusion 101 and the rolling element 2 rotates once is represented by I)Q. In the following description, the angle will be expressed using the above (360/PQ) degree as l'lJ. An alarm 39 is installed in the input/output circuit 35 of the microcomputer.
At the same time, a CPtJ 36 is connected to the input/output circuit 35 via a bus, and a storage device RAM 37 is connected to the CPU 36 via a bus.
．． Connect ROM38. Next, inner ring 1. Rolling element 2. Outer ring 3. Each sensor 5°6.7.
A method for detecting cracks in the bearing 1 according to the present invention will be described in detail using FIGS. 3A to 3A showing the positional relationship of the protrusions 101. Microcracks mainly occur in the inner ring 1 and outer ring 3, but first we will explain the positional relationship between the inner ring 1 and the rolling elements 2 when one microcrack occurs in the inner ring 1, that is, in the open position of the solid line X. do. First, in FIG. 3a and FIG. 3b, which simplifies the configuration shown in FIG.
01 rotates in the direction of arrow a, passes the inner ring position sensor 6, and then rotates by an angle i (corresponds to the count value 1''3 = i of the counter 34), one of the rolling elements 2-4 causes a micro crack b ( Assume that the solid line X mark) reaches the ``2'' side, thereby causing AE to occur and a rectangular wave signal It I- to be output. At this time, the rolling element 2-4 passes the rolling element position sensor 5 and moves in the direction of arrow a at an angle j [count value T2 of counter 29=
j (corresponding to 0≦, J≦P-1)]. At this time]'4-1'3'1゛2
is calculated by the CPU 36. The calculation result is 1”q=i
−j. Next, as shown in FIG. 3c, the inner ring 1 rotates by 1 in the direction a from the position of the inner ring 1 shown in FIG. -3, and as a result, AE is generated and the square wave signal ′■゛1
Suppose that outputs At this time, the angle formed by the rolling elements 2-4 and 2-3 is I)
Since the count value 12 of the counter 29 is a count value counted from the time when the rolling element 2-4 passes the rolling element position sensor 5, the value 12 is expressed as follows. 1'2=j+ (k+-P) -8+P(0≦1゛2≦
P-1) However, Sl is an integer value that satisfies 0≦T2≦P-1, and as mentioned above, the counter 29 is reset every time the number I/value T2 reaches 1). It is a value related to what is happening. At this time, the count value '■'3 of the counter 34 is expressed as follows. 1'+=i++-++PQ (0≦゛1゛3≦PQ-1) However, rl is an integer value to satisfy O≦'1゛3≦I)Q-1, and as mentioned above, the counter 34 is a value related to the fact that the count value Go3 is reset every time it reaches PQ. Therefore, T 4 = 'l' 3-T2 becomes T"q=j-j
+P(J+S+-r+Q). Next, as shown in Fig. 3d, when the inner ring l rotates further from the position of the inner ring 1 shown in Fig. 3c, the rolling elements 2-3
It is assumed that when the crack b reaches below the rolling element 2-2 adjacent to , 8E occurs and a rectangular wave signal ridge T+ occurs. In this case, T2. i, '3 are as follows. T2=j + (kt-P)+ (kt-P)-32P
(0≦'I゛2≦1)-1) T3=i +to ++2-r21)Q (0≦゛1゛3≦I) Q -1) However, S2. Similarly to the above, r2 is 0≦゛1゛2≦P.
-1, 0≦T3≦1) This is an integer that satisfies Q-1, and is a value related to resetting the counter. Therefore, T 4 = T *-1' 2 becomes as follows. T4= i -j +P (2+82- r2Q) Furthermore, in general, the inner ring l rotates by kQ from the previous position where E occurred, and as a result, one of the rolling elements 2 reaches the -L force of crack b, and therefore Assume that AE'h< has occurred and a square wave signal '■''1 has been generated. That is, Q is the ordinal number at which AE has occurred (Q=1 to n), and inner ring 1 is 011 times in αl+1 of AE occurrence. Assume that it is rotated by kc from the position in the a direction. In this case, i"2.1'3 is expressed as follows. (O≦'1゛2≦I)-1) (O≦'1゛3≦PQ-1) However, Sn and rn are 0≦'I゛2≦IFI and 0≦1, respectively.
Values and counters that are integers satisfying ``3≦PQ-1, and are reset each time the counter 29 reaches its count value ``I'' 2 reaches 1). 34 is the count value] 3 is a value related to being reset to fσ leading to PQ. Therefore, l″4 = “1” 3-T 2 becomes as follows. 1'q=j −j 0P (n0Sn −rnQ)
As seen from 2, there is a property that J″4-(i-, i) is an integer multiple of 1).In other words, the next AE
is the initial rotation angle of the rolling element 2-4 when the rectangular wave signal H)l+1 is first output, the count value ゛I''2 (=j) of the counter 29 corresponding to i, and the crack b of the inner ring 1. Based on 5% of the count value T3 (=j) of the counter 34 that corresponds to the initial rotation angle i of the position Y1, it is determined as a function of an integral multiple of the pitch {circle over (2)} of the rolling elements 2. , that is, it has nothing to do with the rotation angle ka of crack b, and as described later, the cumulative addition of '■゛1 becomes 0■ function.Therefore, when AE occurs and the rectangular wave signal 'I゛1 is output for the first time. From then on, we monitor Go1, and when it reaches 'l' where l'q-(i, i) is an integral multiple of P (including zero), there is a possibility that a square wave signal '1'1 is generated. Therefore, when the rectangular wave signal '1'1 is input manually in the CPU 36, i'q (-T3'I
”2), and the calculation result Tqo (-i j
) is stored in the RAM 37. Then enter the count value']'2. 4 is calculated based on T3, and the difference between the calculation result 1 and the above 40 is T 4 - 40
Calculate. The difference 1'4-1" 40 is an integral multiple of P (
(including zero), and if the rectangular wave signal Us is manually generated, 1 is added to the previous value in the memory section at address i'40 provided in the RAM 37. When the AE sensor 7 detects noise and outputs the rectangular wave signal '■'1, l is not repeatedly added to the memory portion of the same memory address in the RAM 37, but the rectangular wave signal '■' is output due to the micro crack. If "1" is being output, "1" is repeatedly added to the same memory address in the RAM 37 (Too address in the above case). FIG. 5 shows the temporal change in the added value, that is, the cumulative number of inputs of the rectangular wave signal T+ to the input/output circuit 35. In the graph not shown in FIG. 5, the vertical axis represents the cumulative number of 11-shaped wave signals 11 human power, and the horizontal axis represents the elapsed time index (R.
'1''), and when the outer ring is fixed and the inner ring rotates as in this embodiment, and a crack has occurred in the inner ring, the elapsed time index is 1.'r is 1.T=X- It is expressed as Q-Y.However, or the number of times the protrusion 101 passes in front of the inner ring position sensor 6, Y is the number of times the rolling element 2 passes in front of the rolling element position sensor 5, and Q is the number of rolling elements 2. In addition, when cracks occur in the outer ring, l(・'I' can be expressed as R = Y. According to Fig. 5, as the micro-cracks grow, the AE becomes stronger and stronger. Therefore, the frequency at which the rectangular wave signal ゛I゛1 is input to the input/output circuit 35 increases, and the cumulative number of 1 inputs increases rapidly. When it exceeds the threshold, an alarm signal is output to the alarm device 39.More preferably, a plurality of the predetermined values are set, and by comparing the cumulative number of one input with the plurality of different predetermined values, cracks can be detected from the initial stage of microcracks. It detects the stage at which the crack is growing until it reaches ultimate failure and displays it on the CRT display 41.This allows the bearing mechanism in which microcracks have occurred to be used to its maximum usable limit. In addition, maintenance and replacement measures can be taken until the usage limit is reached.Furthermore, regardless of whether T1 cumulative human power fj' exceeds a predetermined value, T + cumulative input number increases. By monitoring the rate t an O and issuing an alarm when the H rate t, all 0 exceeds a predetermined value, it is also possible to prevent cracks from growing rapidly and leading to ultimate destruction. ``T'' stored in the RAM 37. After a predetermined time has elapsed after the input of the rectangular wave signal ``I゛1'' at the cumulative number of horns for one person, or after a predetermined rotation fσ of the inner ring 1, the signal is cleared by one sound. 1.1 Remove the cumulative number of manual forces. The above has been described for the case where a micro-crack b occurs in the inner ring 1, but if a micro-crack occurs in the outer ring 3, the counter 29 is When the count value '■゛2 reaches a certain value, the AI 2) will generate a rectangular wave signal '1'. When the wave signal 'l''1 is manually input, the count value T2 input from the counter 29 is stored in △M37, and then manually input; - When the value T2 becomes the stored value, the rectangular wave signal '[1 is manually input] If so, then 1 in the memory r+++ of the address of the same value as the memory value provided in M37.
Add. By comparing the added value with a predetermined value or by comparing the J-11 ratio of the added value with a predetermined value, the occurrence of a crack is detected in the same way as when there is a micro crack in the inner ring 1. Therefore, in this case, the circuit element indicated by 6.30-3/I in FIG. 2 is unnecessary. In the above embodiments, the inner ring 1 rotates and the outer ring 3 is fixed, but the present invention can also be applied to a case where the inner ring is fixed and the outer ring rotates. That is, a protrusion is provided on the outer ring, a sensor corresponding to the inner ring position sensor 6 of the embodiment 1 is provided on the inner ring so as to face the rotation orbit of the protrusion, and the old rolling element position sensor is fixed to the inner ring. Accordingly, the present invention can be applied in exactly the same manner as in the embodiment described above. Further, although the above embodiments have applied the present invention to a bearing mechanism that is a radial bearing, the present invention can also be applied to a bearing mechanism that is a thrust bearing as shown in FIG. That is, the stationary body 61. The stationary body 61
A rotating shaft 629 is rotatably inserted through the rotating shaft 62, a flange 62a protrudes in the radial direction of the rotating shaft 62, provided between the stationary body 61 and the flange 62a, and arranged at equal intervals in the circumferential direction of the rotating shaft 62. In a bearing mechanism consisting of a plurality of rolling elements 63, a rolling element position sensor 64 is arranged opposite to the rotational orbit of the rolling elements 63.
is provided on the stationary body 61, a rotating shaft position sensor 65 is provided on the stationary body 61 so as to face the rotation orbit of the protrusion 62b provided on the flange of the rotating shaft 62, and an AE sensor 66 is provided on the stationary body 61. Therefore, the present invention can be applied in exactly the same way as when the present invention is applied to the bearing mechanism that is the radial bearing. Furthermore, in a bearing (slide) mechanism consisting of a stationary body, a linearly moving body, and a plurality of equally spaced rolling bodies that are movable in the same linear direction and are provided between the solid bodies, the moving body and the moving body The present invention can also be applied to the bearing (slide) mechanism by providing a plurality of protrusions at equal intervals wider than the spacing, and by setting Q to be the number of rolling elements that can fit between the adjacent protrusions. By the way, in the above-mentioned thrust I bearing and slide mechanism, the load is uniformly applied to each of the plurality of rolling elements, and when each of the rolling elements reaches the micro-crack' direction or the r direction, AIE is under the same condition ( A1Σ of the same strength occurs for cracks of the same size). However, in radial bearings, the load is not applied evenly to each of the multiple rolling elements, so even if one of the rolling elements that is not heavily loaded develops a micro-crack, the 8E It doesn't happen much. At this point i
Another embodiment of the radial bearing is not shown in FIG. 7. Hereinafter, only the points different from the previous embodiment will be explained. The parts that are not explained are the same as those in the previous embodiment. In Fig. 7, as shown by the two-dot chain line, 180° is centered around the roll1 minute where the load is applied (toward the -dot chain line-).
The range of /Q (Q is the number of rolling elements 2) is 11 times larger than the load zone. The load zone is a rotation angle range defined by two adjacent rolling elements 2, and is a range in which only one rolling element 2 always exists. A load is applied to the rolling elements 2 existing within the load range, but almost no load is applied to the rolling elements 2 existing outside the load range. The rolling element position sensor 5' is fixed to the outer ring 3, which is a stationary body, so as to face the intersection between the input 1'1 side end of the load zone and the rotating orbit of the moving body 2. The AE sensor 7 is provided on the outer ring 3 on the dashed line, which is the center of the load area. "Micro crack b (solid line X mark) that occurred in inner ring 1"
When one of the rolling elements 2 reaches one side and AE occurs and the square wave signal ``1''1 is input to the input/output circuit 35, the one of the rolling elements 2 passes the rolling element position sensor 5' by an angle j. Assume that it is rotating (that is, the count value of the counter 29 is 1")
2=j). The circuit rotation angle formed by the inner ring position sensor 6 and the rolling element position sensor 5' is S (constant value), and the micro crack b and the inner ring in
If the rotation angle between the inner ring position sensor 6 and the protrusion 101 is L (constant value), the rotation angle between the inner ring position sensor 6 and the protrusion 101 is s
+j−fl; (that is, corresponds to the count value T*=s + , i −1−t of the counter 34). Therefore,
At this time, i'i=i'3-1'2 is '1''q=s-f
It is l. The next time the inner ring 1 rotates in the direction of the arrow a, 8E occurs is when the micro crack b returns to the load zone and reaches below any one of the rolling elements 2. The microcracks [), the rolling elements 2, and the protrusions 101 at that time are shown by broken lines in FIG. If the rotation angle between the rolling element 2 and the rolling element position sensor 5' at this time is j' (that is, equivalent to 1'2 = j'), the relative positional relationship between the micro crack b and the protrusion +01 remains unchanged. From inner ring position sensor 6 and protrusion +
The rotation angle with 01 is s+j'+l; (i.e. i'
: + -8-1-, equivalent to j' ten t). Therefore, in this case, 'l'' 4 =s+L.As will be seen from the following, when Al1 occurs as a load factor, Al1 has the property that it always takes the same value for the same micro-cracks. Therefore, when the rectangular wave signal '1'1 is input, the CPU 36 calculates i and 'q=73-1-2 based on the count values T2 and 'r3 at that time, and calculates the calculated value 1'4.
0 is stored in the RAM 37. Then enter T*. If '1'1 is calculated based on '1'2 and I'l is input when 'I'1 matches the stored calculation value Go1o, the address 'rho' of the RAM 37 is stored. Add 1 to the previous value of the part. With the above configuration, it becomes possible to detect microcracks in a radial bearing more accurately and earlier. In any of the above embodiments, the rectangular wave signal 1 generated by the rectangular wave generator 24 shown in FIG.
The accumulated number of gol inputs is obtained by adding up the values indicating the inputs to the input/output circuit 35 of 1, but another method is to use the rectangular wave generator 24 to generate 8 which increases as the size of the crack increases. A rectangular wave with an amplitude corresponding to the intensity of E (ri'1'1
is generated and the amplitude of the rectangular wave signal T1 is superimposed to obtain ゛I'+
It is also possible to use the cumulative input value n1. According to this method, it is possible to issue an alarm etc. in accordance with not only the frequency of occurrence of AI- but also the intensity of AE. As yet another example, A shown by the solid line in FIG.
FIG. 8 shows a method of detecting microcracks based on changes in the amplitude distribution or duration distribution during a certain minute period of time using a signal after envelope detection of the output signal from the E-sensor 7. This will be explained with reference to FIG. According to this method, the predetermined threshold value (broken line) shown in FIG. 4(d) is set to, for example, 70 d 13, and the amplitude is
A large number of detected signals exceeding dB [solid line in FIG. 4(d)] are detected, and their amplitude values are detected. Figure 8 shows a certain infinitesimal time △l? The distribution situation of the amplitude of the detected signal detected during T is shown. In other words, the horizontal axis shows the amplitude, and the vertical axis shows the respective amplitudes of the horizontal axis. Based on <i
The number of occurrences ΔNT during the minute time ΔR′F in which the '+ signal is present is expressed logarithmically. If Ma is the rate of change in the amplitude value distribution that occurs during the minute time Δ1)'1' marked 01i in FIG.
The Ma is expressed by the following formula. Generally, if the micro-cracks are very small, it is rare for the signal to exceed the predetermined threshold, but
As the crack grows, 8E increases and becomes ゛1゛1
The frequency of signal occurrence increases, and furthermore, 'I' with respect to the amplitude value
′! Signal frequency changes. Therefore, the change rate Ma of the amplitude value distribution is monitored, and when the change rate Ma exceeds a predetermined value, an alarm signal is output from the CI) U 36 to the alarm device 39. In addition, for example, a detected signal exceeding a predetermined threshold value set to 70 dB [dashed line in Fig. 4(d)] [Fig. 4(d)
solid line] [specifically, the pulse width shown in FIG. 4(e)] is detected. Figure 9 shows a certain minute time ΔIt
It shows the distribution of the durations detected during i'. In other words, the horizontal +1l11+ shows the duration, and the vertical 1l11+ shows the duration.
1 has respective durations on the horizontal axis, and the Go 1 signal generated by the micro crack should be generated = 32.Based on the mPf after detection that satisfies the conditions of 1゛4 (1'
NT is expressed logarithmically to the number of occurrences between R'F and a certain minute time of the + signal. In FIG. 9, if the rate of change in the distribution of the duration that occurs during the certain minute time Δ17'F is Md, then the Md is expressed as in the following equation. As the micro-cracks grow, the T1 signal generation frequency with respect to the duration changes, so the rate of change Md of the duration distribution is monitored, and when the Md exceeds a predetermined value, an alarm signal is issued from CI) U36. output to the device 39. As mentioned above, since the distribution change that occurs in the distribution of the amplitude or duration of the output signal from the E sensor 7 during the minute time ΔR'I' is detected, the detection accuracy is Figure 10 is a photograph (100x magnification) of a cut surface of the inner ring where cracks were actually detected by the bearing mechanism crack detection device of the present invention. .Photo: A crack is clearly seen in a part slightly lower than the inner ring surface on one side. Figure 11 is a photograph (1960x) of the fracture surface of another inner ring where cracks were detected, and from this photograph it is possible to observe the origin of the cracks. . The results of energy dispersive elemental analysis performed on the generation origin are shown in the photograph of the analyzer display panel in FIG. 12, which shows that aluminum (ΔQ) is present at the generation origin. (Effects of the Invention) As described in detail above, the present invention provides a stationary body, a working body, and a plurality of stationary bodies arranged between the stationary body and the working body at equal intervals in the working direction of the working body. A bearing mechanism consisting of a rolling element that can be operated freely, a crack detection means that generates a characteristic (F'T) according to a crack that occurs in the bearing mechanism, and a rolling element state detection means that detects the operating state of the rolling element. means, an operating body state detection means for detecting the operating state of the operating body, and a till Il1 means connected to the crack detection means and the rolling element state detection means 9 and the operating body state detection means.
In the crack detection device of H+lt receiver 1117, 1
); Immediately after receiving the characteristic signal from the rack detection means, the control means (j) detects the rolling element state detection means or 1).
ij working body state ra! Next, from the next time onwards, determine the characteristics (the operating state signal that IISJ should input) from the crack detection means described in 015, and then determine the The operating state signal is monitored, and when the operating state signal does not satisfy 1); 1) and the operating state signal is manually input, the characteristic signal is transmitted from the crack detection means.
If the characteristic signal is manually operated, the value indicating the human force of the characteristic signal or the strength of the characteristic signal is not indicated (11'+ is added to the previous value and accumulated, and the bearing mechanism is cracked based on the accumulated value. or detect the amplitude value or duration of the characteristic signal and judge the rate of change in the distribution of the amplitude value or duration detected during a certain minute time. Since it is determined that a crack has occurred in the bearing mechanism, it is possible to accurately detect minute racks occurring in the bearing mechanism. The effort and time required for recovery work can be saved, and damage to peripheral equipment can be prevented.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of a bearing mechanism that is a radial bearing, Fig. 2 is an electric circuit diagram of a crack detection device for a bearing mechanism of the present invention, and Fig. 3a to 3 (Fig. 1 shows an inner ring 1, rolling elements 2, outer ring 3) .Each sensor 5.(i, 7°) An explanatory diagram showing the positional relationship of the protrusion 101, FIG. 4 is a waveform showing how the output of the AE sensor 7 shown in FIG. Figure 5 is a graph showing temporal changes in the cumulative number of inputs, Figure 6 is a cross-sectional view of a bearing mechanism, which is a thrust bearing, and Figure 7 is an embodiment of the present invention shown in Figure 3. FIG. 8 is an explanatory diagram showing another example of
Figure 9 is a distribution diagram of the AE multiplied signal amplitude that occurs during the △
Distribution diagram of the AE double signal duration occurring during the R period, 1st
Figure 0 is a photograph of the metal structure that replaces a drawing of the cut surface of the inner ring where the crack actually occurred, and Figure 11 is a photograph of the fractured surface of another inner ring where the crack actually occurred. The photograph, Figure 12, is a photograph of the analyzer display panel in place of the diagram shown in Figure 11 (showing the results of energy dispersive elemental analysis R11 for the origin of cracks). 1... Inner ring (working body) ), 2. Rolling element, 3. Outer ring (stationary body), 5.. Rolling element position sensor 1 no (rolling element state detection means), 6.. Inner ring position iσ sensor (operating body state detection means), 7.・AE sensor (crack detection means), 35.
36, 37. 38... Input/output device, CPU. 1 is AM, ROM (control means), 39.41...alarm, CR'l'' indicator (alarm generating means).

Claims (1)

[Claims] 1. A stationary body, an operating body, and a plurality of rolling elements disposed at equal intervals in the operating direction of the operating body between the stationary body and the operating body and movable in the operating direction. a bearing mechanism comprising: a crack detection means for generating a characteristic signal in response to a crack occurring in the bearing mechanism; a rolling element state detection means for detecting the operating state of the rolling element; and a rolling element state detection means for detecting the operating state of the operating element. In the crack detection device for a bearing mechanism, the crack detection device includes a working body state detecting means for detecting the crack, and a control means connected to the crack detecting means, the rolling body state detecting means, and the working body state detecting means. Immediately after the characteristic signal is input from the means, the operating state in which the characteristic signal should be input from the crack detecting means from the next time onwards, based on the operating condition signal input from the rolling element state detecting means or the operating body state detecting means. Determine signal conditions, then monitor the operating state signal, and if a characteristic signal is input from the crack detection means when an operating state signal that satisfies the conditions is input, a value indicating input of the characteristic signal. Or, a crack detection device for a bearing mechanism, characterized in that a value indicating the strength of the characteristic signal is added to the previous value and accumulated, and it is determined that a crack has occurred in the bearing mechanism based on the cumulative value. . 2. The control means determines that a crack has occurred in the bearing mechanism when the cumulative value exceeds at least one predetermined value or when the rate of increase in the cumulative value exceeds a predetermined value. A crack detection device for a bearing mechanism according to claim 1. 3. The bearing mechanism is further provided with an alarm generating means that is connected to the control means and generates an alarm signal when the control means determines that a crack has occurred in the bearing mechanism. A crack detection device for a bearing mechanism according to claim 2. 4. A bearing mechanism comprising a stationary body, an operating body, and a plurality of rolling elements disposed at equal intervals in the operating direction of the operating body between the stationary body and the operating body and movable in the operating direction, A characteristic signal is detected in accordance with a crack that occurs in the bearing mechanism, an operating state of the rolling element is detected, an operating state of the operating element is detected, and immediately after the characteristic signal is detected, the rolling element or the Based on the detected working state signal of the working body, determine the conditions of the working state signal under which the characteristic signal should be detected from next time onwards, and then monitor the working state signal to determine the working state signal that satisfies the condition. If the characteristic signal is detected when the characteristic signal is detected, a value indicating that the characteristic signal has been detected or a value indicating the strength of the characteristic signal is added to the previous value and accumulated, and based on the cumulative value. A method for detecting cracks in a bearing mechanism, in which it is determined that a crack has occurred in the bearing mechanism. 5. The bearing mechanism according to claim 4, wherein it is determined that a crack has occurred in the bearing mechanism when the cumulative value exceeds at least one predetermined value or when the rate of increase of the cumulative value exceeds a predetermined value. Crack detection method. 6. The method for detecting cracks in a bearing mechanism according to claim 5, wherein an alarm signal is generated when determining that a crack has occurred in the bearing mechanism. 7. A bearing mechanism comprising a stationary body, an operating body, and a plurality of rolling elements disposed at equal intervals in the operating direction of the operating body between the stationary body and the operating body and movable in the operating direction, A crack detection means for generating a characteristic signal in response to a crack generated in the bearing mechanism, a rolling element state detection means for detecting the operating state of the rolling element, and an operating member state detection means for detecting the operating state of the operating member. and a control means connected to the crack detection means, the rolling element state detection means, and the operating body state detection means, wherein the control means receives a characteristic signal from the crack detection means. Immediately after that, based on the operating state signal input from the rolling element state detecting means or the operating member state detecting means, the conditions of the operating state signal under which the characteristic signal should be input from the crack detecting means from next time onwards are determined. , then monitors the operating state signal, and if a characteristic signal is input from the crack detection means when an operating state signal satisfying the condition is input, detects the amplitude value or duration of the characteristic signal; A crack detection device for a bearing mechanism, characterized in that it is determined that a crack has occurred in the bearing mechanism based on at least one of the amplitude value or the rate of change of the duration distribution detected during a minute time. . 8. A bearing mechanism comprising a stationary body, an operating body, and a plurality of rolling elements disposed at equal intervals in the operating direction of the operating body between the stationary body and the operating body and movable in the operating direction, A characteristic signal is detected in accordance with a crack that occurs in the bearing mechanism, an operating state of the rolling element is detected, an operating state of the operating element is detected, and immediately after the characteristic signal is detected, the rolling element or the Based on the detected working state signal of the working body, determine the conditions of the working state signal under which the characteristic signal should be detected from next time onwards, and then monitor the working state signal to determine the working state signal that satisfies the condition. If the characteristic signal is detected when the characteristic signal is detected, the amplitude value or duration of the characteristic signal is detected, and the rate of change in the distribution of the amplitude value or duration detected during a certain minute time is calculated. A crack detection method for a bearing mechanism, which determines that a crack has occurred in the bearing mechanism based on at least one of the factors.